An electronic still camera, which is now well known, uses an electronic photographing element instead of a photographic film. The electric output signal of the element is electronically processed so that image information is magnetically recorded on a recording medium such as a magnetic disk. The photographing element is often made of an image sensor of 1/2 or 2/3 inch in size. The photographed image area (which is hereinafter referred to as image area) of the element is much less than that of the ordinary photographic film. However, the magnetic disk of the electronic still camera has a size of 54 mm.times.60 mm which is larger than that of the image sensor. The size of a magnetic disk means for driving the magnetic disk is yet larger than that of the disk. When an optical finder is provided in the camera, it is necessary to make the ratio of enlargement high enough to provide such an angle of view as to enable natural viewing. In that case, the volume of an optical system increases as a general rule. Since it is necessary that the still camera can be naturally operated, it is often made nearly equal in size and form to a conventional single-lens reflex camera which employs 35 mm film. Since the optical system and the magnetic disk system of the electronic still camera are large in size, the whole circuit is also large in size and the cost of the camera is likely to be high. If the cost of the electronic still camera is higher than that of the conventional single-lens reflex camera employing the photographic film, the user of the electronic still camera demands that the electronic still camera has a higher functionality. Although the electronic still camera has advantages that the image photographed by the camera can be immediately confirmed and the magnetic disk can be repeatedly used, the camera has a major disadvantage that the quality of the image is considerably lower than that of an image photographed on the photographic film. For that reason, the electronic still camera has not become as popular as the conventional single-lens reflex camera employing the photographic film.
Since the quality of the image photographed by the electronic still camera which sends out a standard television signal is lower than that of the image photographed on the photographic film, the range of objects to be photographed by the electronic still camera is limited. Therefore, if an image of high quality is to be obtained, the camera employing the photographic film needs to be used for photographing.
Since the size of the image made on the image sensor of the electronic still camera is usually smaller than that of the image made on the photographic film, the electronic still camera needs a special lens for the size of the image made on the image sensor. For that reason, if the electronic still camera is of the lens exchange type, an exchangeable lens different in type from that of the conventional single-lens reflex camera needs to be prepared for the electronic still camera.
Since the conventional camera employing the photographic film has an optical finder, the photographer cannot observe the photographed image if he is at a distance from the camera.